The present invention relates to a loader and, more specifically, to structure for mounting a bucket or similar attachment to a loader.
1. Field of the Invention
Many types of structures are available to connect a bucket or other device to the forward end of loader arms. Typically the device either includes a standard semi-permanent mounting arrangement wherein pins or bolts are manually connected between the arms and the attachment, or a relatively complex and more expensive quick coupler located on the arms and latchable automatically during mounting of the attachment. Making the necessary connections and disconnections during mounting and dismounting of the standard arrangement can be time-consuming and inconvenient. To speed mounting and dismounting of the attachment, various types of the quick coupling devices have been made available which reduce the number of times the operator has to leave the operator station during the procedures. Examples of such devices which typically include latching structure mounted on the boom arms are shown in U.S. Pat. Nos. 4,545,720; 3,876,091; 3,672,521 and 3,204,793.
One disadvantage with such boom-mounted devices is that the latching structure is usually locked by dumping or rolling action of the boom linkages; therefore the latch can be inadvertently moved to the locked position without the attachment connected. Once in the locked position, the latch will not permit the attachment to be mounted. Such inadvertent actuation of the latch is time-consuming and frustrating for the operator, and if he is not aware of the locked condition of the latch he can actually damage loader components or the attachment during the unsuccessful mounting attempt. In addition, the condition of the latch often is not readily apparent from the operator station of the vehicle, and the operator may not become aware of an improper connection until he tries to move the attachment.
Another disadvantage with most quick couplings is that they are relatively complex and expensive, and most are not readily adaptable to existing attachments. Some operators, such as those who use the vehicle primarily with the attachment mounted, do not want to pay the premium for a quick coupling that they will seldom use. Therefore, to satisfy the needs of all customers, an inventory of two similar attachments, one with a standard coupling and one with a quick coupling, is required and results in higher manufacturing and distribution costs.
A further disadvantage with most quick couplers is that the normal pivot points for the attachment are moved as much as five to nine inches resulting in adverse changes in the operating dimensions of the device with the attachment mounted. For example, on a front end loader the bucket reach, dump angle, and roll-back angle may be changed detrimentally from the ideal design configuration when a quick coupling is mounted on the boom arms. Bucket dump clearance, maximum lift height, digging depth, bucket to vehicle front hub distance and overall length of the vehicle with the bucket attached are affected as well.